A prominent Iranian lawmaker has blamed the US for the disappearance of Malaysian flight MH370, claiming Washington wants to cause "psychological warfare" between Iran and China.

Hossein Naghavi Hosseini, the spokesman for Iran's Parliament National Security and Foreign Policy Committee, said the missing plane has been "kidnapped" by the US in order to "sabotage the relationship between Iran and China and South East Asia".

"Documents published by the Western media about two Iranians getting on the plane without passports is psychological warfare," he told the Tasnim news agency.

"Americans recruit some people for such kinds of operations so they can throw the blame on other countries, especially Muslim countries."

Officials said that the two men who used forged documents to board the flight had no links to terrorist organisations.

Iran's foreign ministry said it was ready to cooperate in the investigations.

"We have received information on possible presence of two Iranians among the plane's crews. We are pursuing the issue," said Marzieh Afkham, the Iranian foreign ministry spokeswoman.

"We have informed our embassy in Malaysia that we are ready to receive further information about the issue from Malaysian officials. We have announced that we were ready for cooperation."

Confusion still reigns over where MH370 could be, spurred on by Malaysian officials being unable to clarify the plane's last known movements.

There were reports the plane was tracked flying over the Malacca Strait by a military radar – far to the west of its planned route. This would have proved the plane was in the air for more than an hour after it vanished from radar.

"It changed course after Kota Bharu and took a lower altitude. It made it into the Malacca Strait," the unnamed official told Reuters.